Concrete forms are well known in the prior art as used to construct foundation walls for homes, commercial buildings, and the like. Generally, a concrete form consists of a rectangular shaped steel frame approximately two feet wide by eight feet long formed by a two and one-half inch steel plate around the circumference thereof. A small ridge or lip of approximately one-half inch depth is formed around the periphery to hold a sheet of plywood in place therein. The sheet of plywood is supported along its back by metal angles placed at approximately two foot intervals beginning at one foot from the top and bottom of the form.
A plurality of forms are built into two discrete parallel lines between which is poured the concrete which sets up into the completed wall. Adjacent forms are joined to form the walls by hardware which is inserted between matching small rectangular holes cut into the sides of the forms approximately every six inches. Typically, the hardware used at each matched set of holes comprises a pair of slotted pins, one of which is inserted horizontally through the pair of matching rectangular holes and the second of which is inserted vertically through a slot in the first pin. Lastly, a number of "ties" extend between the two walls of the forms and are also secured in place by the hardware. These ties help to hold the forms a constant distance apart and prevent their spreading as the concrete is poured. Typical examples of these forms are found in U.S. Pat. Nos. 3,362,676 and 3,204,918.
Although these forms have been in wide use in the construction industry for many years, there are a number of problems associated with them. Because of the way the adjacent forms are joined or secured to each other, adjacent forms must be almost exactly level. Of course, this requires great attention to excavating and preparing the foundation wall site. However, even with this attention, there are many building sites which have a sloping terrain in which it is not possible to pour an entire length of foundation wall with the same footing elevation. For those installations, a step size can be accommodated, but only in increments equal to the spacing between adjacent rectangular holes in the mold sidewalls. In other words, adjacent panels may be vertically offset from each other by six inches, or a multiple thereof, such that every slot in the side of one concrete form is offset but matches with a corresponding hole in the side of the adjacent concrete form. Of course, not all terrains readily accommodate this step size. Furthermore, much attention must be paid to maintaining or preparing the footing for this step. In common practice, steps of odd sizes are accommodated by "shimming" two-by-fours under a form and other two-by-fours are used to "scab" together the adjacent forms as the attaching hardware will not work as the mounting holes are not aligned. As can be appreciated, this is highly undesirable in that much additional work is required to prepare the forms and there is a much greater likelihood that forms will slip, concrete will be poured improperly, and clean-up work will have to be done to finish off the foundation floor or wall.
The inventor herein is aware of at least two patents which disclose attempts in the prior art at solving the problem of a variable step between adjacent forms. These are U.S. Pat. Nos. 3,429,547 and 4,235,411. The '547 patent discloses a transition member formed of two panel members which are slidingly locked together in a tongue-and-groove arrangement. This transition member fits between two standard sized forms and permits a variable step between these standard concrete form panels. The '411 patent also discloses a transition member which has a slot extending the entire height of each side thereof and special key lock type hardware is used to fit through special cross-shaped holes in the sides of the concrete forms. The key lock is inserted through the cross-shaped holes in the concrete forms, into the transition member slot, and is rotated to lock against the lips which form the vertical slot in the transition member. Both of these prior art disclosures are for a transition member of a particularized and specialized construction. The standardized form is continued to be used, but there is no provision or suggestion as to how a standardized form itself can be used without these specialized transition members, and their attendant specialized hardware. Furthermore, these transition members throw off the standard sizing of the concrete forms, which are typically two feet by eight feet. Therefore, although applicants have become aware of these prior art disclosures as shown in patents, they are not aware of either one of these constructions being actually made and used in the field.
In order to solve these and other problems in the prior art, the inventors herein have succeeded in designing and developing a modification to a standard two-by-eight foot concrete form which permits it to be virtually infinitely variable in alignment between adjacent concrete forms, and yet still be securely fastened together. This invention eliminates the requirement for any transitions, special hardware, or any additional special provisions which must be separately made and installed on the job site. Furthermore, the present invention facilitates the insertion of standardized mounting hardware pins between adjacent concrete forms. As explained above, the rectangular holes provided in the sides of the concrete forms in the prior art required the ground to be almost exactly level such that they would align as they are typically sized to be only slightly larger than the mounting pins themselves. Of course, on the job and in the field, this type of control of a dirt surface which has been excavated is somewhat difficult. Therefore, the inventors herein have developed a cloverleaf shaped slot for the mounting hardware which facilitates the insertion of the mounting pin should one concrete form be slightly offset up or down from its adjacent form. As the pins have a tapered nose, it may be inserted or started into the matched openings and a hammer then used to drive the pin home and thereby level the adjacent forms. This greatly minimizes the amount of manpower needed to place and align adjacent concrete forms over the construction commonly found in the prior art.
In order to provide virtually an infinitely variable step length between adjacent concrete forms, rectangular slots are cut between adjacent cloverleaf mounting holes in each side and, in some cases, top and bottom of the standardized concrete form. These rectangular slots are substantially the same width as the mounting hardware pin and extend substantially the entirety of the distance between adjacent cloverleaf shaped mounting holes. In use, if one concrete form is offset from an adjacent form, the mounting hardware may be inserted through the rectangular slot on one side and the cloverleaf hole on the other side, or vice versa, and still held in place by the second hardware pin which slides through the slot in the first hardware pin. Thus, irregularly offset adjacent concrete forms may be readily joined to each other in a safe and secure fashion. This greatly minimizes the amount of surface preparation which must be made to accommodate sloping terrains requiring steps greater or less than the standard spacing between adjacent mounting holes, typically six inches in the prior art.
While the principal advantages and features of the present invention have been described above, a more complete and thorough understanding of the invention may be attained by referring to the drawings and description of the preferred embodiment which follow.